A novel magnetic composite adsorbent of phenolic compounds based on waste poly(ethylene terephthalate) and carbon-encapsulated magnetic nanoparticles

Abstract

A novel magnetic carbon composite based on carbon-encapsulated iron nanoparticles and waste poly(ethylene terephthalate) was synthesized. The magnetic filler, i.e. carbon-encapsulated iron nanoparticles, was homogenously dispersed in the solution of the carbon precursor. The composites were fabricated by thermal treatment with the aid of three activating agents, KOH, ZnCl₂ and CO₂. The adsorbents were characterized with nitrogen adsorption/desorption analysis, scanning and transmission electron microscopy, Raman and IR spectroscopy, thermogravimetry and magnetometry analyses. The textural properties of the adsorbents were strongly influenced by the content of magnetic filler. The magnetic composites had relatively high adsorption capacities for phenol and its chlorinated derivatives. The adsorption capacity even reached 230 mg g⁻¹, which is comparable to the commercial activated carbon (250 mg g⁻¹). The adsorption kinetics of the composites was generally faster in comparison with activated carbon and the intra-particle diffusion rates were lower for the magnetic composites. The synthesized composites had superior corrosion resistance in comparison with magnetic composites of activated carbon. The magnetic composites had higher regeneration potential than commercial activated carbon.